Humans are newcomers on Earth and it's almost certain that we won't be around, on this planet at least, when the solar system's star finally goes nova. But boffins have identified at least one animal that will be.
It is estimated that our star will die in about five billion years, after growing to a red giant that will most …

Mr Loaf

The power

output of the sun is rising (well its surface temperature is)

In about 1.5 billion years time it will be enough to get earth's average temp to about 60-70 degrees c..... at which point it stops raining and all the water in the oceans ends up in the atmosphere very rapidly.

This increases the green house effect and air pressure at the surface resulting in a runaway action and earth ends up like venus.

Re: The power

I was given to understand that it was a giant Star Goat...

Seriously tho, at the higher temps more water molecules will rise to heights where solar ultraviolet breaks the H-O-H bonds. Then the H will be not so gradually lost to space. It already happened in the case of Mars.

This effect will directly compete with increasing water vapour in our atmosphere, Don't know the rates so I can't speculate, but it might never get to the Venus stage, instead assuming the "dead baked plain" aspect so common in time travel stories.

Re: The power

Re: The power

output of the sun is rising (well its surface temperature is)

ISTR reading somewhere that our sun is a variable of sorts. And we've not been able to measure its temperature for long, barely an eye blink of it's current age, so is it safe to make estimates based on almost no data?

Re: The power

"Enough to fry all life... even Keith Richards"

From past experience I wouldn't be too sure about that. I reckon KR is the real Wolverine even if his tree climbing skills are a little short of Spiderman's. He has consumed or smoked enough uppers, downers or sidewayers to dispose of a fit elephant but, like the poor, he is always with us.

Re: The power

I read that in only 300 million years the Moon and Earth will become tidally locked and the Earth will rotate only once every 28 days - so 14 days at a time of pure darkness, followed by 14 days of nonstop sunlight! Also there will be little to no tides and major ocean currents will change radically or even cease altogether. The moon will only be visible from 1/2 of the earth and will appear in the sky at all times.

Re: The power Tidal Locking

Re: The power Tidal Locking

"It will be about 50 BILLION years before the earth is tidally locked to the moon by which time neither will exist."

It is possible for the Earth to survive the Red Sol phase and even to be somewhat intact and still orbiting after the Solar "Planetary" Nebula phase and into the era of White Dwarf Sol. Earth is rather a large rock with a quite large gooey center and it will take a lot of heat and friction over a long time to kill her.

The Moon is not so sturdy. She's smaller, cooler in the middle, not made of such steely stuff and probably not destined to outlive Red Giant Sol.

The future for Earth, then, may be a dry, dead, moonless, lunar-landscape world orbiting a slowly dying ex-star for the rest of Time.

This is not a totally pessimistic ending. Life could survive it for many, many aeons. If humans invested in deep mining or hardy domes even they - or something that was descended from them - could. It wouldn't be exactly a fulfilling lifestyle full of joy ... there would be no atmosphere.

Here's how they are so tough

Something important they left out is HOW they survive nasty things. Tardigrades in daily life are just as vulnerable as any other aquatic invertebrate. However, they can dry out to around 3% water content, going into suspended animation. In this encysted state, they can withstand gamma rays, hard vacuum, and other conditions meaning certain death to other terrestrial organism. Just add water to rehydrate them and they start foraging.

So it's plausible that encysted tardigrades might be eroded or blasted off the dying Earth. Some might survive to reach other planets or star systems. Granted it's a long shot, but improbable does not mean impossible.

And by the way, they are about the coolest thing you'll ever see through a microscope. Check out some video if you've never seen them.

Re: The power

I read somewhere (in a dependable publication) that the sun is indeed becoming hotter and that in around 800 million years the hottest point of the Earth will reach 100 degrees celsius. That is enough to start the oceans boiling. That's all the time we have, but it is still a lot considering that complex life only appeared 500 million years ago.

Small/far away

Things move...

"Dwarf planets like Pluto and Eris might be able to, but are too far away to be a threat." For now...

Apparently, things in the solar system got very crashtastic for a while as Jupiter spiralled inwards in the very early stages, before being flung out to where it is now by Saturn. It's one of the reasons that there are two bands in the asteroid belt, one rocky and the other icy. Horizon (DailyMotion link).

Re: Primitive Life?

Actually, biologically, there is nothing preventing us for regrowing lost body parts.

Other than normal development and maturity. That is, it is a biological system turned off once at a certain age/development. In our case, extremely early.

Some complex animals do retain it though https://en.wikipedia.org/wiki/Regeneration_(biology) https://en.wikipedia.org/wiki/Axolotl. If it's not beneficial/required for survival, then it is not retained/used in the animal. That does not mean it's impossible, or because it is "more developed".

Re: Primitive Life?

Actually, biologically, it's immune system that prevents you from regrowing lost body parts, call it a trade-off between being able to regrow lost leg or die from something as simple as a rotten fruit or mosquito sting.

This isn't news.

Well, I guess in geologic time it's news, but the Boffins were talking about Keith Richards tardigrades out-surviving the proverbial cockroach in the event of a thermonuclear war when I was a kid. This was back in the early 1960s ... We studied them in elementary school. They are a nice, easy, difficult-to-kill, not dangerous, visible with minimal magnification critter seemingly made specifically for a 7 year old's science project. I called mine "The Michelin Clan".

Sow bugs or roly-polys ...

maybe indirect dependence on other life forms

Life tends to need the ability to utilize energy to survive. The scenarios didn't seem to look very closely at what the environment might be like 10, 100, 1000, 10000 years later. Any life would have to be able to draw energy from that environment, or evolve that ability.

Re: Pfft, the last living thing on Earth will be lawyers...

I guess the question is what makes them so very hard to kill

And can you incorporate any of those mechanisms into things humans can fly in space.

Being able to shut the body down completely for a few decades sounds like it could save a lot of food mass for example, while anything that increases radiation resistance should lower shielding mass, also good if you don't happen to have a convenient sized asteroid handy.

Re: Instant space travel

If you were to take all life on earth and convert it into dna mass wise and blast it into space by the time it got to Alpha Centuri their would be 1 dna molecule for every 100km2 or so. So the chance of a single viable cell landing on a planet even at that close range is pretty slim. For it to find a viable habitat...

Re: Instant space travel

The new you won't have any memory of the old you. Perhaps that's how life got to Earth in the first place. And of course you don't blast them into space naked, you put then into icy or rocky bodies that might become gravitationally attracted to a planet-sized body, out there. Search term: "Hoyle–Wickramasinghe model of panspermia"

For the here and now, the more profitable tack may be to offer, for a price, to attach somebody else's DNA to the junk DNA of a tardigrade.... and either to put it back in the ocean or send it to Mars. Offer not valid where prohibited by law.

the planet has billions of years to play with before the sun goes night-night

Ummm, actually, no.

The sun will swell up into a red giant that will engulf the earth, wiping out the Keithigrades. Ummm, Water Richards. Whatever. Not so much the sun going night-night as going day-day.

A long time after that the sun will become a white dwarf. And a very long time after that the white dwarf will cool off to the point where it is no longer luminous in our visible spectrum. But that will be a really long time after the red giant killed off all the tardikeiths.

Re: the planet has billions of years to play with before the sun goes night-night

How would the swelling of the sun into a red giant affect planetary orbits? From memory Earth is currently outside the projected size of the sun as a red giant, but by then there will be less solar mass and therefore Earth, and other planets, would likely to be further away from the sun due to the reduction in the sun's gravity.

Re: the planet has billions of years to play with before the sun goes night-night

The science fiction angle did immediately jump to my brain

A sort of Plannet of the Apes, where humans (and perhaps most animals) are no more but the Tardis have plenty of time to evolve and fill all vacant ecological niches. Scaled up, the eight limbs can become all sorts of different things. Would they develop eyes, as has happened several time over the evolution of species? Or...?

Fun thoughts. Choosing a hero, now, and working out a future tardi culture: challenging.

Food

Re: Food

True, would there be enough other organisms alive for tardigrades to feed on them? Chemical/energy input has to come into the food chain somewhere therefore they can't survive on other tardigrades for long.

Bearish

In reply to "What do you think about the future of life on this planet?", the answer: "I'm Bearish" would thus be optimistic, rather the opposite of markets. Come to think of it, markets are rather the opposite of nature.

Not Speckless Sky

I think we need to speak with the Water Bears' representatives about the fate of life on earth. I was not able to speak to any Waterbury's, but did achieve the next best thing. Jane Sea-Bear-y says I'd probably be famous if I wasn't such a good Waitress. Just about sums it up, eh?

Last life standing?

That'll be the one with the technical ability, not biological fortitude.

It may seem odd that a human would want to stick around when all around is turning nasty, but never underestimate the madness that underlies our species.

I assume in a few billion years we will have developed materials and mechanisms that would allow us to colonise the surface of the Sun if we so wished, so continuing to live on Earth once it has turned toxic to all life isn't so far fetched.